The United States is moving swiftly and methodically to build the widest possible international support for its war on terrorism.

Nato allies in Europe were the first to come into line. They declared in effect that the destruction wrought in New York and Washington constituted an armed attack on them all.

Nato says it will rally behind

Then the American diplomatic drive moved on to enlist the help of Russia, and of other countries whose help would be valuable in launching any military action against Afghanistan.

The Taleban rulers of Afghanistan have been sheltering the Saudi-born militant, Osama Bin Laden, now formally identified by the Americans as a prime suspect despite denials.

The most ferocious pressure has been put on Muslim Pakistan, one of only three countries in the world to recognise the Taleban as the Afghan Government.

Promises

The Pakistani President, General Pervez Musharraf, promised unstinting co-operation with the US, even though he was caught between a rock and a hard place.

On the one hand, the Bush administration is saying to countries it considers supportive of terrorism: you are either with us or against us - choose whose side you are on.

On the other, hard line religious opinion in Pakistan, led by the militant Islamic groups which have links with the Taleban, will react angrily if the government helps American forces attack Afghanistan.

The Taleban says it will attack those who aid the US

There is also the threat by the Taleban to retaliate militarily against any of their neighbours that do so.

One Pakistani newspaper said the time had come for Pakistan to choose its course; the options were devastating, whichever way it went.

Temptations

It is clear that General Musharraf does not want to have the US as an outright enemy.

That may be the decisive factor pushing him to allow the use of Pakistani air space and agree to seal the border with Afghanistan.

Washington would also like the benefit of the expertise of Pakistani intelligence - its knowledge of Afghanistan, the Taleban and Osama bin Laden.

In any event, the Americans say, Pakistan has agreed to all their requests.

There were incentives for Pakistan to say yes.

The country is still subject to American sanctions, mainly because of the military coup that brought General Musharraf to power. Washington is hinting they might be lifted and some aid restored.

In contrast to Pakistan's obvious agonising, India unhesitatingly offered the US all the help it needed - including logistical aid and the use of Indian facilities as a staging post for military operations.

The Indian Government's promptness enabled it to point the finger at Pakistan and repeat its constant demand that the Pakistani authorities act more effectively against alleged terrorist groups on their own territory.

That is a reference above all to the groups fighting the Indian army in Kashmir.

Mixed bag

Among other states in the region, Turkey and Saudi Arabia may figure in American military plans.

Turkey is worried about domestic Islamist opinion, though it has continued to allow American and British aircraft to fly patrols over Iraq from a Turkish base.

In any event, in the present crisis it is bound as a Nato member by the decision on collective defence.

There are American forces and aircraft stationed in Saudi Arabia.

In fact, their presence is one of the grievances driving Mr Bin Laden. He says they defile the land that contains the holiest places of Islam.

Saudis allowed US operations against Iraq

His views are shared by a substantial section of Saudi opinion.

The government never refers to the presence of American forces, but has many times allowed operations against Iraq from its soil.

The Saudis have promised co-operation, but have declined to say whether they would co-operate in an American attack on Afghanistan. That does not mean they would not.

But the situation is delicate.

Saudi Arabia has been involved in Afghanistan since financing the guerrilla resistance to the Soviet invasion in the early 1980s, and it recognised the Taleban when they took over.

There are inter-Islamic rivalries at play here. The Saudis, like the Taleban, are Sunni Muslims; the Iranians are Shias and are bitterly opposed to the Taleban.

The devastating attacks on New York and Washington have had a dramatic impact in Teheran.

The Ayatollah leading Friday prayers dropped the now-traditional chant of "Death to America" and described the attacks as a catastrophic act of terrorism that must be condemned by all Muslims.

A senior State Department official in Washington said Iran's reaction had been very positive; he would not rule out the possibility of any country working with the US.

It would be unwise to read too much into that remark. But it does show how much international support -- some of it solid, some more fragile -- the Bush administration can potentially wield in its campaign.

Russian relations

The US is devoting a good deal of diplomatic attention to Russia, another key player.

Since the break-up of the Soviet Union the Russians no longer have a direct border with Afghanistan, but they remain influential in the central Asian states which do.

The Russians, like the Chinese, are worried about the spread of Islamic fundamentalism among their Muslim minorities. They have sounded positively eager to work with the Americans.

Co-operation in this crisis could be crucial in building a new relationship with America in which the Russians feel more valued.

They would also like the West to concede that they too face a problem of international terrorism in Chechnya - instead of criticising them for the use of disproportionate force.

But it is not clear what kind of practical support the Russians would give.

They have all but dismissed the idea of military strikes being launched from central Asia. While Russian leaders say force may have to be used, they also urge a careful calculation of the consequences.

So far, Russia's attitude has been markedly more positive than in other recent crises. They have not so far raised questions of international legality, though that could happen once the scope of American action becomes clear.

Jospin: "We are not at war with Islam"

So the Bush administration has succeeded in putting together an extremely broad coalition in quick time. It has been sure-footed, helped of course by a wave of public horror and sympathy around the world.

But it is not a tightly knit alliance. Different countries have different reasons for co-operating, and many want particular things from the United States in return.

Some European members of Nato have voiced their doubts about the future. The French Prime Minister, Lionel Jospin, said solidarity with the United States did not deprive France of freedom of judgement.

He added: "We are not at war with Islam or the Arab-Muslim world."

Even the British Government - Washington's closest ally - said support did not amount to a blank cheque; retaliation must and would be based on hard evidence.

America's allies will want to see that evidence. They will then want to be convinced that the military action decided on is likely to be effective; in particular, that it will not simply kill large numbers of civilians and increase the supply of fanatics willing to die to inflict suffering on the West.

The truth is that it will probably be impossible to be sure. And the United States, however deliberately it proceeds, will ultimately do what it considers right with or without the support of the world.